In recent years, demands for electric double layer capacitors, in which an electric double layer formed in an interface between a polarizing electrode and an electrolyte is utilized, as backup power sources have been rapidly increasing. Attention has been paid also to the application thereof to articles for which a large capacity is required, such as a power source for an electric vehicle, and a high electrode density has been desired for making the capacity thereof larger.
An electrode for an electric double layer capacitor is usually produced by dissolving or dispersing a binder into water or an organic solvent, mixing this with an active material for an electrode and optional materials, such as an electroconductivity additive, to prepare a slurry composition for an electric double layer capacitor electrode, applying this to a current collector made of aluminum foil or the like, and then drying the applied composition. Conventionally, as the binder, there has been generally used a fluorocarbon polymer such as polytetrafluoroethylene, or polyvinylidene fluoride. However, in the electrode produced by use of the fluorocarbon polymer, the binding force between its active material for an electrode and its current collector is insufficient. Additionally, the electrode density thereof is low.
Suggested is a binder using, a polymer which has a specific glass transition temperature and a specific particle diameter as a binder which exhibits a good binding force even if a small amount thereof (see Patent Document 1). However, despite the use of this binder, the binding force between the active material for an electrode and the current collector is insufficient, further, the electrode density is also low.    Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 11-162794